gimple.c (gimple_fold_obj_type_ref): Removed (a replacement moved to gimple-fold.c).

2010-05-13  Martin Jambor  <mjambor@suse.cz>

	* gimple.c (gimple_fold_obj_type_ref): Removed (a replacement moved to
	gimple-fold.c).
	* gimple-fold.c (get_base_binfo_for_type): New function.
	(gimple_get_relevant_ref_binfo): Likewise.
	(gimple_fold_obj_type_ref_known_binfo): Likewise.
	(gimple_fold_obj_type_ref): Likewise.
	(fold_gimple_call): Simplify condition for folding virtual calls
	and call gimple_fold_obj_type_ref.
	* gimple.h (gimple_get_relevant_ref_binfo): Declare.
	(gimple_fold_obj_type_ref_known_binfo): Likewise.

	* testsuite/g++.dg/otr-fold-1.C: New test.
	* testsuite/g++.dg/otr-fold-2.C: New test.

From-SVN: r159362

1 files changed, 133 insertions, 13 deletions

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index ab07634..4fb1b3f 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -1401,6 +1401,137 @@ gimple_fold_builtin (gimple stmt)
   return result;
 }
 
+/* Search for a base binfo of BINFO that corresponds to TYPE and return it if
+   it is found or NULL_TREE if it is not.  */
+
+static tree
+get_base_binfo_for_type (tree binfo, tree type)
+{
+  int i;
+  tree base_binfo;
+  tree res = NULL_TREE;
+
+  for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
+    if (TREE_TYPE (base_binfo) == type)
+      {
+	gcc_assert (!res);
+	res = base_binfo;
+      }
+
+  return res;
+}
+
+/* Return a binfo describing the part of object referenced by expression REF.
+   Return NULL_TREE if it cannot be determined.  REF can consist of a series of
+   COMPONENT_REFs of a declaration or of an INDIRECT_REF or it can also be just
+   a simple declaration, indirect reference or an SSA_NAME.  If the function
+   discovers an INDIRECT_REF or an SSA_NAME, it will assume that the
+   encapsulating type is described by KNOWN_BINFO, if it is not NULL_TREE.
+   Otherwise the first non-artificial field declaration or the base declaration
+   will be examined to get the encapsulating type. */
+
+tree
+gimple_get_relevant_ref_binfo (tree ref, tree known_binfo)
+{
+  while (true)
+    {
+      if (TREE_CODE (ref) == COMPONENT_REF)
+	{
+	  tree par_type;
+	  tree binfo, base_binfo;
+	  tree field = TREE_OPERAND (ref, 1);
+
+	  if (!DECL_ARTIFICIAL (field))
+	    {
+	      tree type = TREE_TYPE (field);
+	      if (TREE_CODE (type) == RECORD_TYPE)
+		return TYPE_BINFO (type);
+	      else
+		return NULL_TREE;
+	    }
+
+	  par_type = TREE_TYPE (TREE_OPERAND (ref, 0));
+	  binfo = TYPE_BINFO (par_type);
+	  if (!binfo
+	      || BINFO_N_BASE_BINFOS (binfo) == 0)
+	    return NULL_TREE;
+
+	  base_binfo = BINFO_BASE_BINFO (binfo, 0);
+	  if (BINFO_TYPE (base_binfo) != TREE_TYPE (field))
+	    {
+	      tree d_binfo;
+
+	      d_binfo = gimple_get_relevant_ref_binfo (TREE_OPERAND (ref, 0),
+						       known_binfo);
+	      /* Get descendant binfo. */
+	      if (!d_binfo)
+		return NULL_TREE;
+	      return get_base_binfo_for_type (d_binfo, TREE_TYPE (field));
+	    }
+
+	  ref = TREE_OPERAND (ref, 0);
+	}
+      else if (DECL_P (ref) && TREE_CODE (TREE_TYPE (ref)) == RECORD_TYPE)
+	return TYPE_BINFO (TREE_TYPE (ref));
+      else if (known_binfo
+	       && (TREE_CODE (ref) == SSA_NAME
+		   || TREE_CODE (ref) == INDIRECT_REF))
+	return known_binfo;
+      else
+	return NULL_TREE;
+    }
+}
+
+/* Fold a OBJ_TYPE_REF expression to the address of a function. TOKEN is
+   integer form of OBJ_TYPE_REF_TOKEN of the reference expression.  KNOWN_BINFO
+   carries the binfo describing the true type of OBJ_TYPE_REF_OBJECT(REF).  */
+
+tree
+gimple_fold_obj_type_ref_known_binfo (HOST_WIDE_INT token, tree known_binfo)
+{
+  HOST_WIDE_INT i;
+  tree v, fndecl;
+
+  v = BINFO_VIRTUALS (known_binfo);
+  i = 0;
+  while (i != token)
+    {
+      i += (TARGET_VTABLE_USES_DESCRIPTORS
+	    ? TARGET_VTABLE_USES_DESCRIPTORS : 1);
+      v = TREE_CHAIN (v);
+    }
+
+  fndecl = TREE_VALUE (v);
+  return build_fold_addr_expr (fndecl);
+}
+
+
+/* Fold a OBJ_TYPE_REF expression to the address of a function.  If KNOWN_TYPE
+   is not NULL_TREE, it is the true type of the outmost encapsulating object if
+   that comes from a pointer SSA_NAME.  If the true outmost encapsulating type
+   can be determined from a declaration OBJ_TYPE_REF_OBJECT(REF), it is used
+   regardless of KNOWN_TYPE (which thus can be NULL_TREE).  */
+
+tree
+gimple_fold_obj_type_ref (tree ref, tree known_type)
+{
+  tree obj = OBJ_TYPE_REF_OBJECT (ref);
+  tree known_binfo = known_type ? TYPE_BINFO (known_type) : NULL_TREE;
+  tree binfo;
+
+  if (TREE_CODE (obj) == ADDR_EXPR)
+    obj = TREE_OPERAND (obj, 0);
+
+  binfo = gimple_get_relevant_ref_binfo (obj, known_binfo);
+  if (binfo)
+    {
+      HOST_WIDE_INT token = tree_low_cst (OBJ_TYPE_REF_TOKEN (ref), 1);
+      return gimple_fold_obj_type_ref_known_binfo (token, binfo);
+    }
+  else
+    return NULL_TREE;
+}
+
 /* Attempt to fold a call statement referenced by the statement iterator GSI.
    The statement may be replaced by another statement, e.g., if the call
    simplifies to a constant value. Return true if any changes were made.
@@ -1428,9 +1559,6 @@ fold_gimple_call (gimple_stmt_iterator *gsi)
     }
   else
     {
-      /* Check for resolvable OBJ_TYPE_REF.  The only sorts we can resolve
-         here are when we've propagated the address of a decl into the
-         object slot.  */
       /* ??? Should perhaps do this in fold proper.  However, doing it
          there requires that we create a new CALL_EXPR, and that requires
          copying EH region info to the new node.  Easier to just do it
@@ -1438,19 +1566,11 @@ fold_gimple_call (gimple_stmt_iterator *gsi)
       /* ??? Is there a good reason not to do this in fold_stmt_inplace?  */
       callee = gimple_call_fn (stmt);
       if (TREE_CODE (callee) == OBJ_TYPE_REF
-          && lang_hooks.fold_obj_type_ref
-          && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR
-          && DECL_P (TREE_OPERAND
-                     (OBJ_TYPE_REF_OBJECT (callee), 0)))
+          && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR)
         {
           tree t;
 
-          /* ??? Caution: Broken ADDR_EXPR semantics means that
-             looking at the type of the operand of the addr_expr
-             can yield an array type.  See silly exception in
-             check_pointer_types_r.  */
-          t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee)));
-          t = lang_hooks.fold_obj_type_ref (callee, t);
+          t = gimple_fold_obj_type_ref (callee, NULL_TREE);
           if (t)
             {
               gimple_call_set_fn (stmt, t);